1. Field of the Invention
The present invention relates to a computer system in which a computer, a storage device, and a switch are connected to a network, and in particular to a switch for virtualizing a storage (virtualized storage is hereinafter referred to as virtual storage) while keeping the computer system operating (hereinafter referred to as storage virtualization switch).
2. Description of the Related Art
Recently, in accordance with increase in an amount of data, a Storage Area Network (SAN) which is a technique for connecting a computer and plural storage devices by a network (switch) has been used. According to this SAN technique, it becomes possible to cope with sudden increase in the amount of data by connecting the storage devices to the switch at any time. However, as the number of storage devices in a computer system increases, since ports for the switch connecting the computer and the storage devices becomes insufficient, addition of switches is required.
In the related art, installation of a switch in an existing computer system is realized by connecting one of free ports of a switch in the system and one port of the switch to be added with a network (see “IBM Total Storage SAN Switch: Using the 2109 Model M12”, [online], [retrieved on Jan. 10, 2003], Internet address location: “www.1.ibm.com/support/docview.wss?uid=ssg1S7000313&aid=1”, pages 59 to 63). According to the above-mentioned technique, it is possible to install the switch while keeping the system operating.